title: Pulse pressure variation and stroke volume variation to predict fluid responsiveness in patients undergoing carotid endarterectomy.
abstract: BACKGROUND
  During carotid endarterectomy (CEA), hemodynamic stability and adequate fluid management are crucial to prevent perioperative cerebral stroke, myocardial infarction and hyperperfusion syndrome. Both pulse pressure variation (PPV) and stroke volume variation (SVV), dynamic preload indices derived from the arterial waveform, are increasingly advocated as predictors of fluid responsiveness in mechanically ventilated patients. The aim of this study was to evaluate the accuracy of PPV and SVV for predicting fluid responsiveness in patients undergoing CEA.
  
  
  METHODS
  Twenty seven patients undergoing CEA were enrolled in this study. PPV, SVV and cardiac output (CO) were measured before and after fluid loading of 500 ml of hydroxyethyl starch solution. Fluid responsiveness was defined as an increase in CO ≥ 15%. The ability of PPV and SVV to predict fluid responsiveness was assessed using receiver operating characteristic (ROC) analysis.
  
  
  RESULTS
  Both PPV and SVV measured before fluid loading are associated with changes in CO caused by fluid expansion. The ROC analysis showed that PPV and SVV predicted response to volume loading (area under the ROC curve = 0.854 and 0.841, respectively, P < 0.05). A PPV ≥ 9.5% identified responders (Rs) with a sensitivity of 71.4% and a specificity of 90.9%, and a SVV ≥ 7.5% identified Rs with a sensitivity of 92.9% and a specificity of 63.6%.
  
  
  CONCLUSIONS
  Both PPV and SVV values before volume loading are associated with increased CO in response to volume expansion. Therefore, PPV and SVV are useful predictors of fluid responsiveness in patients undergoing CEA.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Hallym University Dongtan Sacred Heart Hospital, Hwaseong, Korea.
authors.forename: Kyung Mi
authors.initials: KM
authors.lastname: Kim
authors.forename: Mi Sook
authors.initials: MS
authors.lastname: Gwak
authors.forename: Soo Joo
authors.initials: SJ
authors.lastname: Choi
authors.forename: Myung Hee
authors.initials: MH
authors.lastname: Kim
authors.forename: Mi Hye
authors.initials: MH
authors.lastname: Park
authors.forename: Burn Young
authors.initials: BY
authors.lastname: Heo
keywords: Arterial blood pressure; Cardiac output; Carotid endarterectomy; Fluid therapy; Stroke volume